San Diego  It’s the case that anyone with a cellphone should be paying attention to.

The 2009 arrest of a San Diego gang member has sparked a nationwide debate over whether law enforcement should be able to search cellphones without a warrant.

The U.S. Supreme Court is set to tackle the question Tuesday morning, as lawyers give oral arguments in the case that has already drawn sharply divided opinions nationwide on the balance between privacy and public safety.

The case is being closely watched by civil rights advocates, law enforcement, scholars and citizens alike. Briefs on the matter from outside groups have poured in for the high court’s consideration — with those opposing warrantless searches outnumbering supporters.

Yes
16% (206)

No
84% (1081)

1287 total votes.

But the supporters wield a strong voice, representing a wide range of the country’s largest associations of law enforcement and prosecutors, who say public safety will be put at risk if such searches are curbed.

What makes this particular case unique, and modernizes the debate, is the involvement of a smartphone: One of the central themes being argued is whether law from an era of rotary dial phones should apply to today’s smartphone technology.

The case stems from a traffic stop in San Diego. A police officer noticed David Leon Riley had expired tags, then found he had a suspended license. A search of the Lexus before the car was towed revealed two guns stashed in the engine compartment.

The officer arrested Riley and scrolled through his Samsung smartphone, looking through his text messages and noticing indications of gang activity. A gang detective hours later searched deeper into the phone at the police station.

A photo on the phone showed a red Oldsmobile suspected in a shooting weeks earlier in which no one was hit.

His lawyers said the images in the phone helped prove Riley’s gang ties, while prosecutors say other physical evidence tied him to the shooting.

A first jury deadlocked but a second convicted him. He is now serving 15 years to life in prison for of attempted murder and other charges — the sentence enhanced by the gang involvement.

Along with Riley’s case, the Supreme Court on Tuesday is to hear a similar case against a Boston drug dealer, Brima Wurie, on the issue of a warrantless search of a basic flip phone.

But it’s the legal issues around the smartphone that really have people fired up. Courts around the country are already divided on the matter.

Current case law allows police to seize and search items within a person’s reach upon arrest, most importantly to be able to disarm him or prevent him from destroying evidence. But how far does that reach extend? And what items apply?

State and federal attorneys argue that police can search anything — diaries, wallets and letters — found on or near an arrestee, so why not cellphones?

Lawyers for Riley, and many other civil liberties groups, contend today’s smartphones store much more personal information.

Riley’s attorneys compare smartphones to carrying around the equivalent of the desk, file cabinets and bookshelves you’d find in an 18th-century house, as well as medical records, random thoughts, financial records and even intimate videos.

“With each passing year, the smartphone will only become more of a nerve center for our daily activities, relationships, and very identities,” his lawyers write in a brief to the court.

They don’t dispute that police should be able to seize the phone upon arrest, but they argue authorities should not examine its contents until obtaining a warrant, a process that can be done within the hour and over a phone. Or at the very least, they contend, police should only search a phone if the officer has a reasonable suspicion it contains evidence of a crime.

Legal scholars Charles MacLean and Adam Lamparello say even that narrower standard would “leave much room for manipulation” by police.

“Warrantless searches of cellphone memory — after a suspect has been arrested, and after law enforcement has seized the phone — would have been unconstitutional at the time the Fourth Amendment was adopted, and are unconstitutional now,” the professors at Indiana Tech Law School write in their own brief to the court. “Simply stated, they are unreasonable.”

A wide consortium of the nation’s law enforcement officials and prosecutors say limiting their ability to search immediately is “bad public policy.”

They present hypothetical worse-case scenarios, a car bomb in front of a courthouse or a kidnapped child, for example, and are concerned that having to wait for a warrant could jeopardize human life.

But they also provide actual past instances in which suspects were able to have their cellphones remotely erased, in Houston and Orange County, before authorities could get a warrant. And, they argue measures that could block a signal to prevent a seized phone from being remotely erased is not foolproof.

Authorities point to the password lock feature on iPhones as particularly troubling, saying that once the lock is engaged, it can’t be broken by anyone but the techs at Apple in Cupertino. Their brief contends the company often takes two months to respond to legal requests to get into the phones.

The federal government, in its argument, said limiting the scope of a search would be reasonable and would prevent officers from searching phones in minor arrests or traffic-related offenses in which there would be no reasonable expectation of evidence on the phone.

It’s tough to predict how the court will lean. The justices have already issued opinions in two other Fourth Amendment cases that favor law enforcement this year.

Just last Tuesday, in Navarette v. California, the court ruled 5-4 that police can use anonymous tips to make traffic stops. And in February, in Fernandez v. California, a 6-3 decision held that a roommate’s consent to search a house is valid, even if the subject of the search does not give police permission.

Riley’s lawyers have been practicing dry runs, holding moot argument sessions at Stanford University, UCLA and Georgetown University in the weeks leading up to the main event.

Riley’s San Diego-based lawyer Patrick Ford likened arguing before the Supreme Court to “fending off spears.”

Attorneys will usually only get a minute or two into their prepared arguments before the justices begin peppering them with questions.

“The goal is to figure out what’s bothering them, and they’re not shy about telling you, they let you know right away,” Ford said of the justices. “They are thoughtful questions.”

Making the oral argument in Riley’s case will be Stanford law professor Jeffrey Fisher, one of the nation’s leading Supreme Court litigators.

Arguments are to begin at 10 a.m., with Fisher arguing 25 minutes, and saving his last 5 minutes at the end for rebuttal. The state’s solicitor general is to argue 20 minutes and cede its last 10 minutes to the federal government.

Arguments in the Wurie case will follow. Then they will have to wait — days, weeks — for a decision.